docs: def read_adc_difference(self, differential):
          """Read the difference between two channels.  Differential should be a
          value of:
            - 0: Return channel 0 minus channel 1
            - 1: Return channel 1 minus channel 0
            - 2: Return channel 2 minus channel 3
            - 3: Return channel 3 minus channel 2
            - 4: Return channel 4 minus channel 5
            - 5: Return channel 5 minus channel 4
            - 6: Return channel 6 minus channel 7
            - 7: Return channel 7 minus channel 6
          """
          assert 0 <= differential <= 7, 'Differential number must be a value of 0-7!'
          # Build a difference channel read command.
          command = 0b10 << 6                  # Start bit, differential read
          command |= (differential & 0x07) << 3  # Channel number (in 3 bits)
          # Note the bottom 3 bits of command are 0, this is to account for the
          # extra clock to do the conversion, and the low null bit returned at
          # the start of the response.
          resp = self._spi.transfer([command, 0x0, 0x0])
          # Parse out the 10 bits of response data and return it.
          result = (resp[0] & 0x01) << 9
          result |= (resp[1] & 0xFF) << 1
          result |= (resp[2] & 0x80) >> 7
          return result & 0x3FF